The present invention relates to wireless communication, and more particularly to wireless communication devices with multiple antennas and receivers.
Mobile communication devices or terminals are becoming ubiquitous in modern society. Typical mobile communication devices include pagers, personal digital assistants, mobile phones, and the like, however, all such devices shall be referred to herein as mobile terminals. Consumers that use mobile terminals as part of their every day activities have three primary concerns: size and weight, performance, and battery life. Consumers that carry two or more mobile communications devices, such as a pager and a mobile phone, want the devices to be as small and unobtrusive as possible. As a result, there is increasing pressure to shrink the mobile terminal and its internal components.
Further, consumers demand that their mobile terminals provide adequate reception for their needs. A common problem associated with wireless communications is that the transmitted signals are sometimes lost or distorted because of multipath fading and interference. One known method of reducing interference and multipath fading is to use a plurality of antennas, and more preferably a plurality of receivers. Thus, the mobile terminal may include two receiver circuits, which are then utilized together using interference cancellation or other known performance enhancing techniques to provide a clear audio signal for the user in the case of a voice call and improved data throughput in the case of a data call. However, this dual receiver methodology is also in direct conflict with the goal of size reduction.
Lastly, consumers are very concerned about the battery capacity of the mobile terminals, and especially the operating time that the battery provides before it needs to be recharged. However, this concern is at odds with the desire to miniaturize the mobile terminals and the desire to improve reception with a plurality of antennas and receivers. The additional circuitry adds a drain on the battery, thereby increasing the frequency of recharging and/or the size of the battery. While advances have been made in the size and weight of the battery, pressures to make the mobile terminals smaller and lighter have frequently exceeded the ability of the battery designers to produce a battery that supplies the needed power for the desired long interval between recharging while fitting within the condensed mobile terminal.
Therefore, there is a need for manufacturers of mobile terminals to improve the performance of mobile devices while still conserving energy.